Electrical switch.



No. 744,924. l j PATBNTBD Nov. 24, 1903. H. C R. LCMAX C J. TCMLINSCN. ELECTRICAL SWITCH.

N0 MODEL.

INVENTORS WITN Hlamax E SES y El. a/ J. Toflloh M By th ein.: attorney used.

NITE STAmnc atented tovember 24C, 1903.

Ammer @einem HENRY LQMAX, RALPH LoMAX, AND JOHN ToMLINsoN, on DARwnN,

ENGLAND.

ELECTRICAL SWlTCl-i..

SPECIFICATION forming part of Letters Patent No. 744,924, dated November 24, 1903.

Application filed October 18, 1902. Serial No. 127,866. (No model.)

Be it known that we, HENRY LoMAX, RALPH Our invention relates to the kind of elecV trical switches for which an application for Letters Patent in the United States dated October 18, 1901, and serially numbered 79,069 has been filed by us, in which switches a crank-pin on a tumbler-lever is so actuated by a torsional spring that after being turned past its dead-center it turns the tumbler-lever into its end position, and the latter carries the contact or switch lever with it, thus closing and breaking the circuit suddenly.

Our invention consists in improvements in the construction of said switches, the object of which is to simplify the construction and reduce-the size and cost of the switch and to render the action absolutely certain.

On the drawings annexed hereunto,Figurel shows a side view of the improved switch with the cover in section; Fig. 2, a vertical section along line .fr on Fig. 3; Fig. 3, a top view; Fig. 4., a horizontal section along line 'y y of Fig. 1; Fig. 5, a similar section along line e e; Fig. 6, another horizontal section through the base; Fig. '7, a view of the under side of the knob.

On the drawings a two-way switch is shown as an example to illustrate our improvement.

To the base d, consisting of non-conductive material, as usual, the metal plate b is fixed by means of two studs b' b2, screwed into or otherwise fixed to the same, and of the terminal b3, which are securedto the base ct by nuts in recesses on the under side. To the terminal b3 the wire from one pole of the dynamo or its equivalent is connected. For a two-way switch two insulated spring-contacts c and c are fixed to the base a in the usual way and form terminals connected by wires to the other pole. For Lan ordinary makeand-break switch only one such contact is On or to the plate b a central spindle d is fixed in any convenient way. A crank or tumbler e is mounted loose on the spindle d and can be turned by the knob f, which has the usual sectoral recess to turn the tumbler for part of its revolution and thenvallow it to complete its movement by the action of the spring hereinafter described. Between the tumbler e and the metal plate b the switch or contact lever 71, is mounted loose on the spindle d, having at its end a boss h', adapted to make a conductive connection between the contacts c or c' and the plate and terminal b3. At the other end the lever 7?, is formed concentric with the spindle and with two semicircular abutments or recesses h2 h5, into which the crank-pin e', fixed to or formed on the tumbler e, lits. This crank-pin passes through a slot 7l in the plate b, the slot being concentric with the spindle d. This slot extendsthrough a longer arc than the arc between the recesses h2 h3, the latter being, forinstance, as shown, diametrically opposite each other, while the slot extends for two-thirds of a circle. Below the plate?) the crank-pin is connected by a link Z to the straightened end of a torsional spring m, which is mounted on a stud m', fixed on the plate b and fastened with its other end to this stud. The base d is recessed to receive the crank-pin, link, and spring.

By placing the spring and link underneath the plate h and on the same side of the center as the switch-lever the link Z is in tension and can be made of wire, as shown, with one end bent round a groove in the crank-pin e and the other end formed into an eye Z', through which passes the hooked end m" of the spring fm, which cheapens the cost of the switch. It also leaves the top of the plate free for the switch-lever, and the size of the switch can be reduced. By making the annular distance between the recesses h2 h3 on the switch-lever 7L considerably longer than half the length of the slot t the crank when the tumbler is turned till the pin has passed its dead-center opposite to the terminal h3 is pulled over to the other side by the spring for some distance before it encounters the opposite recess, and thus strikes the switch-lever with a blow, which renders the sticking of the lever impossible and effects its reversal very rapidly. The ends of the slot t' act as stops for the crank-pin, rendering separate stops unnecessary. The ends of the studs Z2 b2 stand up above the plate b and act as stops for the lever, preventing it from moving too far.

The spring mis placed on the opposite side of the spindle CZ to the arc described by the crank-pin e', the link Z passing under the said spindle when the said crank moves from one to the other end of the slot t'.

By removing one ot' the contacts c or c the two-way switch shown on the drawings is converted into an ordinary make and -break switch.

We claim as our inventionl. In an electrical switch, the combination ot a base, terminals on said base, a metal plate secured on said base and in conductive connection with one of said terminals, a spring-contact in conductive connection with the other terminal, a spindle fixed on the said plate, a tumbler loose upon said spindle, a crank-pin on said vtumbler extending below said plate, a link connected by one end to said crank below said plate, a torsional spring connected to the other end of said link and adapted to pull the crank into eitherofits end positions after it has passed its dead-center, a switch-lever mounted loose upon the spindle and adapted to close and break the circuit between said terminals, abutments on said lever adapted to be struck by said crank-pin after it has passed its dead-center in either direction, and a knob adapted to turn the tumbler till the crank-pin has passed its deadcenter and then to release it.

2. An electrical switch consisting of the combination of a base, a metal plate having an arcuate slot and secured on said base, terminals attached to said base, one of said terminals having electrical connection with said plate, a spring-contact having electrical connection with a second of said terminals, a

spindle fixed on said plate and projecting upwardly therefrom, a tumbler loose on said spindle, a crank-pin on said tumbler projecting below said plate through said slot, the throw of said crank-pin being limited by said plate at the ends of said slot, a stud fixed to the lower side of said plate, a torsional spring Wound aboutand having one end secured to said stud and having its other end free, said spring being located on the opposite side of said spindle from said slot, a link connecting said crank-pin to the free end of said spring, said spring putting a tension on said link, a switch-lever loosely mounted upon the said spindle and capable of closing and breaking the circuit between said terminals, abutments on said lever in the path of said crank-pin after it has passed its dead-center, and a manualiy-operated knob loosely mounted on said spindle and having a lost-motion engagement with said tumbler.

3. In an electrical switch, the combination of a switch-lever, a tumbler for controlling the same, a hand-knob for turning the tumbler,a spindle on which said tumbler isloosely mounted, a crank-pin on said tumbler, stops limiting the movement of said crank-pin, a torsional spring located on the opposite side of said spindle to the arc described by said crank-pin, and a link connecting said spring to said crank-pin, said spring exerting a tension on said link in adirection approximately away from said spindle.

In testimony whereof we have hereunto set our hands in the presence of two witnesses.

HENRY LOMAX. RALPH LOMAX. JOHN TOMLINSON. Witnesses:

CARL BOLL, RIDLEY JAMES URQUHART. 

